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 # Copyright (c) 2015-21, NVIDIA CORPORATION. All rights reserved.
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 # are met:
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 #    contributors may be used to endorse or promote products derived
 #    from this software without specific prior written permission.
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#pragma once
#include "ScriptBindings.h"
#include <functional>

// Forward declaration.
struct ImGuiInputTextCallbackData;

namespace Falcor
{
    class FALCOR_API Console
    {
    public:
        /** Clears the console.
        */
        void clear();

        /** Renders the console and handles important keyboard input events:
            - The "`" key is used to open/close the console.
            - The ESC key is used to close the console if currently open.
            - The UP/DOWN keys are used to browse through the history.
            \param[in] pGui GUI.
            \param[in,out] show Flag to indicate if console is shown.
        */
        void render(Gui* pGui, bool& show);

        /** Processes console input. Should be called once at the end of every frame.
            \return Returns true if some processing occured.
        */
        bool flush();

        /** Global console instance.
            \return Returns the global console instance.
        */
        static Console& instance();

    private:
        Console() = default;

        void enterCommand();
        std::optional<std::string> browseHistory(bool upOrDown);
        static int inputTextCallback(ImGuiInputTextCallbackData* data);

        std::string mLog;
        char mCmdBuffer[2048] = {};
        std::string mCmdPending;
        std::vector<std::string> mHistory;
        int32_t mHistoryIndex = -1;
        bool mScrollToBottom = true;
    };
}
